The invention relates to a solar heating device of the type in which room air exits the room adjacent the floor and enters a tube-type solar collector where it is heated and returns to the room at the top of the collector. These devices depend on convection, with heated air rising and cooler air being drawn into a lower inlet to provide a siphoning effect. The temperature of the air exiting from the outlet varies depending on the extent of solar radiation at the moment and the temperature of the incoming air.